Investigations of the neuroeffector mechanism in vascular tissue will focus on a number of specific objectives: the definition of the basis of variation and characteristics of blood vessels of different size and location; the quantitation of the vascular neurogenic response mediated through beta adrenergic receptors; the development of the neuroeffector mechanism in umbilical, placental and fetal vascular tissue; the response of the vascular neuroeffector to a rapid rise in intravascular pressure and the basis of regulation of the neuroeffector relationship.